1. Field of the Invention
This method relates to a pipe connection method and connecting structure. More specifically, it relates to the connection method and connecting structure of lance pipe used to blow oxygen into the steel bath in, for example, an open-hearth furnace or electric furnace.
2. Description of the Prior Art
The lance pipe used to blow oxygen into the steel bath in an open-hearth furnace or electric furnace can be exposed to, for example, temperatures of 1800.degree. C. and therefore wear easily. Pipes which have become shorter can be reused by connecting them with suitable joints. In this case the lance pipes must be connected by air-tight joints to prevent oxygen from leaking out.
Until now, lance pipe connections have been made by inserting the ends of the lance pipes into opposite ends of a cylindrical joint member and compressing the ends to seal them shut. In this method it is difficult to position the lance pipe ends near the center of the joint member and the pressure fitting can easily be uneven, allowing oxygen to leak out. In addition, since the ends of the joint members are separately compressed into the ends of the lance pipes by a hydraulic device, it is difficult to improve the efficiency of the work.